Hi Laura, thanks for your note. No we did not use sand under the flagstone steps, they are set within the gravel and do not need any sand or stone dust. I hope this helps! Good luck with your project. Robert

Thanks...one last thought do they stand up to high traffic walking?

I am using river stone, can you comment,as to whether or not they may set easily among the stone?

Hi Laura, I'm assuming that by river stone, you mean a larger 1"-2" stone...if so you will need a base course of stone dust or sand to set the stepping stones in so they wont shift or slide. It will be important to use a level to make sure each step is level and consistent. They should hold up well in to high traffic walking. Hope this helps. Good luck with your project. Robert

looks like Del Rio river rocks